ATHENS, Greece (AP) - Greek authorities continued their search and rescue operation following the sinking of a trawler overcrowded with migrants in one of the deepest parts of the Mediterranean Sea, the country’s coast guard said early Saturday afternoon.

The coast guard said that one Greek Navy frigate and four other vessels are operating 47 nautical miles (54 miles; 87 kilometers) southwest of the town of Pylos in Greece’s southwest. Earlier, two helicopters from the navy and coast guard had joined the operation, the coast guard said.

To date, 104 survivors have been rescued and 78 bodies have been retrieved from among the passengers of the trawler that carried as many as 750 men, women and children from Syria, Egypt, the Palestinian territories and Pakistan. No survivors or bodies have been found since Wednesday, the day of the accident.

Greek authorities continue to face criticism, however, over their failure to act more quickly. They say the migrants insisted they didn’t need any help, but NGOs say they received a number of calls for help.

The survivors have been taken to a migrant reception center outside Athens. A few have been visited by relatives residing in other European countries.